The election of Abraham Lincoln in 1860 was the final straw for many southerners. In all 11 states seceded from the Union. Four of these (Virginia, Arkansas, North Carolina, and Tennessee) did not secede until after the Battle of Fort Sumter that occurred on April 12, 1861. Four additional states were Border Slave States that did not secede from the Union: Missouri, Kentucky, Maryland and Delaware.

In addition, the area that would become West Virginia was formed on October 24, 1861 when the western portion of Virginia chose to break away from the rest of the state instead of seceding.

The ordinances of secession were the actual legal language by which the seceded states severed their connection with the Federal Union. The declarations of causes are where they tended to disclose their reasons for doing so, although only Georgia, Mississippi, South Carolina, Texas and Virginia issued separate declarations of causes.

The political theory of the time among secessionists required that the act of secession be carried out by a specially elected convention or by referendum. In this sense the "secessions" of both Missouri and Kentucky were flawed, as neither was carried out in this manner. The Missouri secession ordinance was passed by a rump legislature and never approved by the people at large. The Kentucky secession ordinance was adopted by a convention of 200 participants representing 65 counties, held in Russellville.

These are offered in chronological order. If the state convention passed a declaration of causes document, then it will be listed at the bottom of the ordinance document.